PCB Trace Width Calculator
A copper trace on a circuit board can only carry so much current before it heats up, and undersizing it risks a burned track. This calculator sizes the trace for you using the widely used IPC 2221 relationship. Enter the current in amps, the copper weight or thickness in ounces per square foot, and the temperature rise you will accept above ambient, then choose whether the trace runs on an external or an internal layer, since internal traces cool more slowly and need to be wider. The tool returns the minimum trace width in millimetres and mils. External traces can be narrower because they shed heat to the air, while inner layer traces are derated. This is essential for power rails, motor drivers and anything carrying meaningful current. Enter your values and read a safe width instantly. Everything runs locally in your browser, so it is fast and private.
How to use PCB Trace Width Calculator
- Enter the trace current in amps.
- Enter the copper thickness in ounces.
- Enter the allowed temperature rise in degrees.
- Read the minimum trace width for internal and external layers.
Frequently asked questions
What standard does the trace width calculator follow?
It uses the IPC-2221 charts that relate current, allowed temperature rise and copper cross section to the minimum safe trace width.
Why do internal traces need to be wider than external ones?
Internal layers dissipate heat poorly because they are buried in the board, so for the same current they need a wider trace than an exposed external layer.
How does copper thickness change the result?
Thicker copper, measured in ounces per square foot, carries more current per unit width, so a heavier copper weight allows a narrower trace for the same current.
What is PCB Trace Width Calculator?
A copper trace on a circuit board can only carry so much current before it heats up, and undersizing it risks a burned track. This calculator sizes the trace for you using the widely used IPC 2221 relationship.
Is PCB Trace Width Calculator free to use?
Yes. PCB Trace Width Calculator is completely free, with no sign-up and no usage limits.
Does PCB Trace Width Calculator work in a web browser?
Yes. PCB Trace Width Calculator runs in any modern web browser. There is nothing to download or install.
Is my data private with PCB Trace Width Calculator?
Yes. PCB Trace Width Calculator runs entirely on your device in your browser, so nothing you enter is uploaded to a server.
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